Research On Linear Frequency Modulated Continuous Wave Radar Short Range Detection Signal Processing Technology

Compared with pulse radar,Linear Frequency Modulated Continuous Wave(LFMCW)has the advantages of simple radar system composition,high range resolution,high receiver sensitivity,low interception,and anti-interference.It is widely used in the short-range detection of "Low,Small,and Slow" targets.However,in LFMCW radar difference-frequency signal processing,there are also some problems,such as ranging errors caused by FFT technology’s "fence effect," clutter,and low SNR random noise interference.In this paper,the research work on the above problems is as follows.Firstly,the mathematical model of LFMCW radar difference frequency signal is established.Aiming at the short-range detection of "Low,Small,and Slow" targets,the difference frequency signal models of the single target are analyzed and established respectively under the three conditions of stationary uniform motion and arbitrary low-speed motion.Considering the noise interference of the receiver,a general static multi-target difference frequency signal model is established.Finally,the difference frequency signal model expression of complex multi-target detection scenes,including motion and static,is generalized.Secondly,the CZT algorithm analyzes the narrow-band spectrum of LFMCW radar difference frequency signal.When FFT technology is used to estimate the frequency of the difference frequency signal,the ranging error caused by the "fence effect" is difficult to meet the requirements of short-range detection and high-precision ranging.In this paper,the CZT algorithm and four other algorithms are selected to process the different frequency signal of LFMCW radar.The short-range detection of the above algorithm under the experimental conditions of SNR=-5～10d B low SNR and other simulation experiments show that the CZT algorithm under low SNR average absolute error is more petite.That is,the CZT algorithm can improve the accuracy of radar ranging better.Therefore,this paper chooses the CZT algorithm for narrow band analysis of LFMCW radar difference frequency signal spectrum.Thirdly,design and implement LFMCW radar difference frequency signal processing flow and simulation experiment.This paper analyzes the signal detection model of LFMCW radar difference frequency signal under Gaussian noise interference,then designs the LFMCW radar difference frequency signal processing scheme based on the model,and determines the MTI,MTD,CFAR detection algorithms for further processing LFMCW radar difference frequency signal.Focus on the MTI-MTD-CZT cascade algorithm.Then,the LFMCW radar short-range detection signal processing simulation experiment is completed in the complex scene.The computer simulation experiment verifies the MTI-MTD-CZT cascade algorithm’s effectiveness in radar signal processing to improve the accuracy of LFMCW radar short-range detection and range and suppress clutter.